1. Field of the Invention
The present invention relates to a train control system, and particularly to an on-board device mounted on a train to control the speed of the train and the like based on train control information received from ground-side equipment.
2. Description of Related Art
In general, a train control system is configured such that an on-board device mounted on a train controls the speed of the train and the like based on train control information received from ground-side equipment to ensure the safe traveling of the train. As a conventional train control system, there is known a train control system in which loop coils (or track circuits), ground coils, and the like, as the ground-side equipment are electromagnetically coupled to a receiver, an on-board coils, and the like, that constitute the on-board device, to transmit and receive train control information, or a train control system in which the train control information is transmitted and received between wayside radio sets as the ground-side equipment and vehicle radio sets that constitute the on-board device (refer to Japanese Laid-Open Patent Publication No. 2010-36803, Japanese Laid-Open Patent Publication No. 2008-162548).
The conventional on-board devices can receive train control information only from ground-side equipment of a train control system using signals of the same type and/or the same kind. Therefore, trains traveling through a zone (train line) along which ground-side equipment of a specific train control system are installed are limited to those with an on-board device for the specific train control system mounted thereon.
With the development of railroad networks, the need to make trains travel through zones each using train control systems of different types or the need to employ train control systems of different types in some parts of a zone may arise. However, it is difficult for the conventional techniques to meet such a need.
Furthermore, when an existing system is changed to a new system, there is a need to achieve a balance between commercial operations by the existing system and the adjustment of the new system during the transition. Therefore, upon changing the system, an on-board device for the new system must be added to trains with an on-board device for the existing system mounted thereon, and after the completion of the adjustment of the new system, the on-board device for the existing system must be removed. In other words, the trains need to be altered at least twice, and this requires much time and effort at system change.